Knob-billed duck

The knob-billed duck (Sarkidiornis melanotos), also known as comb duck belongs to the family Anatidae.
The knob-billed duck is distributed in sub-Saharan Africa, Madagascar, Pakistan, India, Indochina and southern China. In South America it is distributed in Paraguay, Brazil and Argentina.

There are two subspecies, namely, Sarkidiornis melanotos melanotos and Sarkidiornis melanotos sylvicola. The IUCN (International Union for Conservation of Nature) has categorized and evaluated these duck species and has listed them as of "Least Concern".

These knob-billed ducks are large birds, males measuring 65 to 80 cm in length and weighing 1,300 to 2,900 grams. The female birds weigh 1,200 to 2,300 grams. In adults the white head is freckled with dark spots.
The neck and the underparts are white. The upper parts are glossy blue black. The secondaries have bluish and greenish iridescence. The males are larger than the females and have a large black knob on the bill.

These duck species feed on plant matter, seeds, grasses, shoots, small fish and invertebrates. They inhabit marshes, swamps, rivers, lakes, rice fields and inundated floodplains. These ducks breed during the rainy season.